Believe me, I wish the athletic bubble of my life (ski racing and cycling friends) was representative of the general population. Healthy, successful, engaged... However, the other compartments of my life (professional and family) have shown me the fit/healthy are a small portion of the general population. It all boils down to resources, environment, and interest, and they're all intertwined.
How many high school kids even think amateur bike racing is a "thing"? If you don't catch them before that point, you're probably not going to get another shot until their settled in their lives, if at all. Generally speaking, there relatively small windows of opportunity to bring them in. If you catch them when they're young, even if they leave the sport for a while, the possibility is still in their mind later in life. Mid-30s and on can be more problematic, with their own kids and other demands competing for attention, not to mention all of the other "sexy" fitness opportunities out there.